酸浆豆腐中产酸菌的耐高温紫外诱变

乳酸菌在食品及食品发酵行业具有广泛的应用,其中以乳酸菌发酵酸浆作为凝固剂的酸浆豆腐已逐渐成为人们关注的热点。酸浆豆腐发酵过程中以乳酸菌为优势菌,在酸浆豆腐点浆时,需在75℃以上高温下进行。普通乳酸菌无法耐受此温度且大量失活,影响产品的后熟。为了开发耐高温乳酸菌,以课题组从云南建水豆腐酸浆中分离的菌株为出发菌,通过紫外诱变的方式,温度梯度筛选获得4株耐高温产酸性能好的菌株。诱变获得4株菌均可在75℃耐高温30 min并保持较好的活性和产酸效果。研究所得突变菌株相比原始菌株均具有更好的耐热性和产酸性。其中HCUL 1.1801-1912Z活性最强、产酸能力最好,为4株菌中最优菌株,将该菌株用于发酵生产酸浆豆腐,将显著提高乳酸菌在豆腐中的活性和豆腐的品质。

High Temperature Resistant Mutation of Acid-Producing Strains in Acid Tofu Whey by Ultraviolet Radiation

Lactic acid bacteria(LAB)is widely used in food and food fermentation industries.Among them,acid whey tofu with LAB as coagulant has gradually obtained more and more attention.LAB is the dominant bacteria in the fermentation process of acid whey tofu,which was inevitable above 75℃during the pasting process of acid whey tofu.Ordinary LAB cannot tolerate this temperature,and a large number of inactivation at this temperature will affect the ripening of the product.In order to develop high temperature resistant LAB,four strains of high temperature resistant and acid producing bacteria were screened by ultraviolation mutagenesis with the strains isolated from Jianshui acid tofu whey in Yunnan province.The results showed that the four strains could resist high temperature at 75℃for 30 min,and maintained a good activity and acid-producing ability.Compared with the original strain,the mutant strains obtained in this study had better temperature resistance and acid-producing ability.Among them,HCUL 1.1801-1912Z had the best activity and acid-producing ability and it will significantly improve the quality of acid whey tofu.The activity of the LAB in the tofu and tofu quality can be obviously improved.